January 24-25: Miracle or Mirage

[TSSN+]

5 minutes ago, CAPE said:

Latest blend. I think we got us a solid signal across guidance for a major winter storm lol

Assume that’s 10:1 too?

[csnavywx]

1 hour ago, WxUSAF said:

Really good consensus for this range. Steady as she goes. 

Good thing about the 6Z GFS coming into line is that this lessens the risk from the southern stream/cutoff. It was consistently the slowest and most guidance has trended slower and stronger with it over time. Gives some confidence in it not getting stuck or coming out too piecemeal. We have other potential issues, like interaction with the trailing NS wave, but the big failure modes are getting crossed off first.

[ravensrule]

Just now, TSSN+ said:

Assume that’s 10:1 too?

I don’t believe the NBM has a Kuchie. 

[CAPE]

Just now, TSSN+ said:

Assume that’s 10:1 too?

I would assume so.

[TSSN+]

1 minute ago, CAPE said:

I would assume so.

You have the qpf map? 

[300 square feet]

22 minutes ago, WxUSAF said:

Digital red = lots of digital blue

 

Anyone know where to find this graphic on LWX’s page? It used to be under winter weather, but it’s not there anymore

[CAPE]

1 minute ago, TSSN+ said:

You have the qpf map? 

[nj2va]

Not everyday we see a high in the low 20s with snow likely.

Sunday

Snow likely. Mostly cloudy, with a high near 22. Chance of precipitation is 60%.

[nj2va]

1 minute ago, 300 square feet said:

Anyone know where to find this graphic on LWX’s page? It used to be under winter weather, but it’s not there anymore

Thanks to @NorthArlington101 for the link  https://www.weather.gov/lwx/wintermaps

Days 3-7 Threat

[TSSN+]

2 minutes ago, CAPE said:

Thanks. Must have ratios cause gives me 9” on .6 qpf in 

[bncho]

See what happens if we have a good STJ?

[GreyHat]

1 minute ago, TSSN+ said:

Thanks. Must have ratios cause gives me 9” on .6 qpf in 

Magnolia Delaware at 1.08 qpf in

 

[GreyHat]

1 minute ago, bncho said:

See what happens if we have a good STJ?

Yeah,  but we also need sampling of the players. Some of the posters from the old would say, wait till the players are on the field and sampling begins. 

[aldie 22]

7 minutes ago, CAPE said:

Yeesh hope that isn't ice down in central N.C that would be a disaster

[Scraff]

First cup of Irish coffee successfully downed. Duh! Overnight runs were absolute art. Big shout out to those brave souls who sacrifice sleep so my morning forum read feels elite. Or that could just be the coffee. Hmmm. Anyway, what the hell was I saying? Oh right! Keep up the great analysis people! Should be a phenomenal day of juiced up model runs. LFG Mofo’s!! 

[EstorilM]

Yikes I’ll be at Wisp with my friends this weekend for an annual ski trip - coming home on Sunday to NoVa should be interesting. 
 

This after the HIGH on Saturday is going to be 7 degrees! 
 

I guess I asked the weather gods for winter weather for the weekend so - can’t complain. 

[CAPE]

11 minutes ago, TSSN+ said:

Thanks. Must have ratios cause gives me 9” on .6 qpf in 

Yeah looks like it factors in multiple variables for SLR.

[ravensrule]

14 minutes ago, aldie 22 said:

Yeesh hope that isn't ice down in central N.C that would be a disaster

If the Euro comes to fruition, they’re honestly screwed. 

[CAPE]

6 minutes ago, CAPE said:

Yeah looks like it factors in multiple variables for SLR.

Google AI-

Key Methods for Determining Snow Ratios in NBM:

• Temperature-Based Algorithms: The SLR is highly dependent on boundary layer and low-level temperatures (surface to 850 mb). Generally, colder air results in higher ratios (fluffy, dry snow), while temperatures near freezing produce lower ratios (wet, dense snow).
• Melting Rates for Marginal Temperatures: For temperatures at or above 32°F, the NBM v4.2 incorporates idealized melting rates. The total SLR is reduced based on the ratio of melting to accumulating snow, effectively lowering the ratio if the snow melts as it falls.
• Dynamic/Algorithm-Based Ratios: Instead of a default 10:1, the NBM uses algorithms that consider factors such as:
  • Wind Speed: Higher wind speeds can lead to lower ratios due to snowflake fracturing.
  • Cloud Structure: The presence of supercooled water droplets (higher riming) vs. depositional growth influences the ratio.
• Ensemble Member Blending: The NBM uses output from several models (HRRR, GFS, ECMWF) to calculate a probabilistic snowfall, utilizing the best-performing models to determine the most likely ratio for a given area.
• Elevation Adjustments: Ratios are adjusted upward at higher elevations to account for colder, drier conditions in mountainous terrain. 

[Eskimo Joe]

 

 

[CAPE]

27 minutes ago, Scraff said:

First cup of Irish coffee successfully downed. Duh! Overnight runs were absolute art. Big shout out to those brave souls who sacrifice sleep so my morning forum read feels elite. Or that could just be the coffee. Hmmm. Anyway, what the hell was I saying? Oh right! Keep up the great analysis people! Should be a phenomenal day of juiced up model runs. LFG Mofo’s!! 

At first glance I read that as " Big Stout" lol. Which reminds me I need to get some before the weekend. OK back on topic!

[Nomz]

I’d like for models to work their way a little north today but I’m just feeling greedy. I’ll take the 1 inch qpf in DC at 10:1+ ratios

[bncho]

That 6z Euro looked like it was going to develop some decent coastal as well. Might've been 15-20" if it had played out to its end.

[SomeguyfromTakomaPark]

1 minute ago, Nomz said:

I’d like for models to work their way a little north today but I’m just feeling greedy. I’ll take the 1 inch qpf in DC at 10:1+ ratios

I think the trends on the Euro the last 2 runs will probably continue and you will be happy.  The big NAO settling in this weekend should slow things down and promote phasing.  The look at 144 on 6z euro with a deepening low off Hatteras moving basically north with fresh arctic air in place is the kinda thing that we don't see often and can really offer us a lot of QPF with fantastic ratios.

[Terpeast]

3 minutes ago, Nomz said:

I’d like for models to work their way a little north today but I’m just feeling greedy. I’ll take the 1 inch qpf in DC at 10:1+ ratios

Careful, we don’t want too much too fast. I am 90% sure the storm will come up north anyway. I’m thinking the mix line will reach as far north as EZF/SoMD despite the models saying it’ll stay south of the NC/VA border. 

[TSSN+]

2 minutes ago, Terpeast said:

Careful, we don’t want too much too fast. I am 90% sure the storm will come up north anyway. I’m thinking the mix line will reach as far north as EZF/SoMD despite the models saying it’ll stay south of the NC/VA border. 

The north trend! 

[T. August]

Hopefully we can get this thing under D5.5 today

[snowfan]

9 minutes ago, Nomz said:

I’d like for models to work their way a little north today but I’m just feeling greedy. I’ll take the 1 inch qpf in DC at 10:1+ ratios

Its Tuesday, pace yourself. No one in the DMV should be clamoring for north movement just yet.

[Stormchaserchuck1]

9z SREF way north early fwiw

 

[WxUSAF]

3 minutes ago, T. August said:

Hopefully we can get this thing under D5.5 today

Yeah I’d like to stop slowing down…get this back to starting late Saturday would be nice.